n it. It had, then, last been used to enter the rocket, not to leave it.

* * * * *

Thad opened the exhaust valve, let the air hiss from the chamber of the lock. The huge door swung open in response to his hand upon the wheel, and he entered the cylindrical chamber. In a moment the door was closed behind him, air was hissing into the lock again.

He started to open the face-plate of his helmet, longing for a breath of air that did not smell of sweat and stale tobacco smoke, as that in his suit always did, despite the best chemical purifiers. Then he hesitated. Perhaps some deadly gas, from the combustion chambers....

Thad opened the inner valve, and came upon the upper deck of the vessel. A floor ran the full length of the ship, broken with hatches and companionways that gave to the rocket rooms, cargo holds, and quarters for crew and passengers below. There was an enclosed ladder that led to bridge and navigating room in the dome above. The hull formed an arched roof over it.